Fixing Omnikey Ultra

[Rezene]

I just bought an Omnikey Ultra T and it was in way worse condition internally than I expected. The switches were pretty much unusable, but I cleaned those up and they feel pretty nice. I have nos ones coming in so I'm not too worried about them. What I am worried about is that I'm pretty sure coffee got spilt in it because there was brown splotches on some keycaps and the pcb smelt burned and there was a brown glaze over part of it. The numpad 5 key registers as constantly pressed even when I took the switch apart. The space bar chatters sometimes and sometimes it doesn't even register. The 9 key isn't working at all even when I took the switch apart and pushed the contacts together manually. Other than those problems it works good as new. How would I go about fixing these things? Is it possible

[ZedTheMan]

Assuming there are white alps, what I would do first is take a multimeter and see if the nonworking keys can provide continuity when pressed. If not, and for the ones that chatter, I would recommend trying to solder in some of the working switches and seeing if they work then. If they do, at that point, the NOS switches should work when they come in. If not, keep us updated, and I'll see what I can come up with.

[Darkshado]

Did you just take apart the switch tops or did you desolder them?
Beside suspected coffee in this instance, old keyboards often have *lots* of rosin flux on the bottom, I've seen this on both AEK IIs and AT101s, wouldn't be surprised old Focus boards have the same.
Is this a single layer and single sided PCB or something more modern? If the former, try cleaning the bottom (isopropanol + cotton swabs should work) and see if you still get a stuck switch on numpad 5. If it's something more modern then you may have no choice but to desolder all the switches to clean the top of the PCB as well. You can check the board's functionality without having to resolder by jumpering switch vias.

[Rezene]

Did you just take apart the switch tops or did you desolder them?
Beside suspected coffee in this instance, old keyboards often have *lots* of rosin flux on the bottom, I've seen this on both AEK IIs and AT101s, wouldn't be surprised old Focus boards have the same.
Is this a single layer and single sided PCB or something more modern? If the former, try cleaning the bottom (isopropanol + cotton swabs should work) and see if you still get a stuck switch on numpad 5. If it's something more modern then you may have no choice but to desolder all the switches to clean the top of the PCB as well. You can check the board's functionality without having to resolder by jumpering switch vias.

I don't have a soldering iron right now so I just took apart the switch tops. How can I tell if it is a single layer PCB or something more modern? I can take pictures when I get home

[ZedTheMan]

Did you just take apart the switch tops or did you desolder them?
Beside suspected coffee in this instance, old keyboards often have *lots* of rosin flux on the bottom, I've seen this on both AEK IIs and AT101s, wouldn't be surprised old Focus boards have the same.
Is this a single layer and single sided PCB or something more modern? If the former, try cleaning the bottom (isopropanol + cotton swabs should work) and see if you still get a stuck switch on numpad 5. If it's something more modern then you may have no choice but to desolder all the switches to clean the top of the PCB as well. You can check the board's functionality without having to resolder by jumpering switch vias.

I can assure you that omnikeys have vigorous coatings of rosin flux.

To the OP, jumpering the switch vias is probably the best way to tell if its switch side or keyboard side in your situation

All the northgates I've dealt with have been single layer with jumper wires.